جستجوی مقالات مرتبط با کلیدواژه "xrd" در نشریات گروه "فیزیک"

Shewanella RCRI7 has the ability to reduce uranium under anaerobic conditions. Bacterial function of one- and ten-day cultured colonies in terms of uranium removal ability, morphological changes and viability in anaerobic solution containing uranium and nitrate has been investigated in this study. The results showed that one-day bacteria grew faster than ten-day bacteria at a concentration of 2 mM Uranium, while the uranium removal percentage of ten-day bacteria is higher than that of one-day bacteria, which are adsorbed by the bacterial masses through biosorption. Bioremediation of uranium in one-day cultured bacteria was confirmed by XRD analysis, spectrophotometry and morphological examination by light microscopy. 4-month and 9-month samples from one-day colony had 96% and 99% uranium removal, respectively, indicating the stability of soluble uranium removal over long periods of time. One-day and 4-month samples containing nitrate and uranium also confirmed the ability to remove uranium in the presence of nitrate at a concentration of 20 g /L, which shows the ability of this native bacterium to reduce the uranium in the presence of nitrate, introducing this as a suitable option for future studies.

Zr-1%Nb alloy is the most common alloy used as nuclear fuel cladding in Russian reactors. In producing a nuclear fuel cladding, the cold rolling (pilger) and the final straightening lead to the creation of residual stresses and a change in the distribution of these stresses within the fuel cladding. The residual stresses are known to be effective in increasing the hydride fraction in nuclear fuel pods formed under working conditions by hydrogen adsorption of water and have destructive effects. In this study, the residual stresses created in different stages of fuel cladding fabrication, including samples before annealing, post-annealing, and straightening, were measured using X-ray diffraction and splitting. In addition, the amount of hydride fraction in different samples was evaluated. The effect of annealing on the orientation of hydrides was performed in annealing at 500, 540, and 580 °C for 4 hours.

The electron accelerator located at Yazd is working with tap water as cooling. This equipment is made of carbon steel (A37). This steel, as a typical carbon steel, is very susceptible to corrosion destruction in uncontrolled condition. Using tap water as a coolant, has led to high corrosion and thus blocked water circulation paths. XRD and XRF analysis of corrosion products from different parts of accelerator showed that a large quantity of these sediments is composed of Iron Oxide. SEM images indicated that the sediments have a Tubculation morphology. Also, the ICP-OES results showed that in comparison with Yazd tap water, the chemistry of the cooling water circulating in the accelerator has been changed, consequently its hardness decreased by passing time. The results obtained from the Langelier parameter showed that the water exiting from the end of the cooling system is a little corrosive. Due to the color and morphology of corrosion products, the corrosion mechanism is a Tubculation type.

 In this research, the layers of the sedimentary environment of the Pabdeh formation, which have different variation amounts of phosphate minerals (Apatite), were studied. The XRF and XRD analyses were performed for determination of the minerals and the radioactive elements, REEs and compounds for 54 selected samples (with high amounts of P2O5). According to the importance of the geochemical elements relations and their interpretation, the statistical analysis methods cluster analysisand principal component analysis, (PCA) were used. According to the results of the component correlation matrix, after rotation through the direct oblimin method, and normalizing with Kaiser method, the amounts of components and the ratio between them are well illustrated and the XRF results were divided into two principal components.

The aim of the present work is a synthesis and investigation of the structural properties of tungsten trioxide (WO3) nanoparticles. The prepared samples were calcined at 400 and 450˚C. The structural, compositional, morphology and molecular properties of the samples were investigated by using X-Ray Diffraction, Scanning Electron Microscopy, Energy-Dispersive X-Ray Spectroscopy and Fourier Transform Infrared Spectroscopy, respectively. The structural parameters of the samples were studied by the Size-Strain Plot (SSP) method. The results show that the particle size increases with increasing calcination temperature and the amount of impurities also decreases. The photocatalytic activity of the tungsten trioxide nanoparticles was evaluated by the photocatalytic discoloration of methylene blue in aqueous solution.

In this paper, the effect of Sb and Pb doping on the critical current density and microstructure of Bi1.6PbxSbySr2Ca2Cu3Oz (BPSSCCO) were studied. The BPSSCCO superconductor was made by a solid state reaction method. The superconductivity properties of Pb- and Sb-doped Bi-based superconductor, such as critical current density, flux pinning energy and microstructure, have been investigated. In order to study the effect of Sb and Pb on the critical current density of the samples, the V-J curves were measured at 77 K temperature. The critical current density of the Sb-doped samples at 77 K temperature increases when the amount of Sb is increased. In addition, for all the samples, the relationship between the current and voltage in the mixed state region is found to follow the model relationship of V = aIb.

The sol-gel technique has been used in the preparation of Cd doped Bi1.64Pb0.36Sr2Ca2-xCdxCu3O10 ceramic superconductors. In this study, the value of doping Cd has been varied from x = 0-0.2 at different annealing times (32, 48, 56 and 64h) for preparing samples. To find the temperature of annealing, TGA analysis has been done from dried gel. Analysis of XDR and SEM has been done to study the morphology and microstructur of samples. The results of XRD indicated that the maximum values of the Bi-2223 phase percent was obtained for sample doped with x = 0.02 Cd. Also, the study of SEM images shows that this sample has a plate like structure which is caused increase in the critical current density. The critical current density and the critical temperature of samples have been measured by four-probe method. The results show that the sample which was doped with x = 0.02 has maximum value of percentage of Bi – 2223 phase, critical current density and critical temperature

In this research, lead hexaferrites nanoparticles (PbFe12O19) were prepared by sol-gel method. The effect of pH on the structural and magnetic properties of PbFe12O19 was studied. The attempt in this paper was to depict the effect of change in sol-gel pH on the size and morphology of the samples as well as their structural and magnetic properties. Therefore, samples with pH = 1.8, 3, 5, 6, 7, and 8 were prepared. Then, the dry gels of the samples were heated in the optimum annealing temperature and time of 800 oC and 3 h, respectively. In order to study the structural, morphological and magnetic properties of the samples prepared in various pHs X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Vibration Sample Magnetometer (VSM), and LCR meter were applied, respectively.

Ag، Au nanoparticles and Ag-Au nanocomposite were prepared by co-deposition of RF-sputtering and RF-PECVD from acetylene gas and Ag، Au targets. Atomic structure and topography were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM)، respectively. UV-Visible spectra samples indicated that the activity of Ag and Au nanoparticles in the vicinity of each other increased as the time passed. This result indicated that Ag-Au nanocomposite films demonstrate a higher activity in comparison to Au or Ag nanoparticles thin films. Furthermore، these nanocomposites showed a higher sensitivity in the vicinity of DNA with low concentrations of fM in comparison to Au nanoparticles thin films.

In this paper، ZnO thin film was prepared by sol-gel process on glass substrates. The deposited films were dried at 100 and 240 ˚C and then annealed at 300، 400 and 500 ˚C. The two-probe measurement showed that resistance of as-prepared films is very high. The KrF excimer (λ=248 nm) laser irradiation with 1000 pulses، frequency of 1 Hz and 90 mJ/cm2 energy on surface of film resulted in the reduction of the films electrical resistance. X-ray diffraction (XRD) patterns confirmed the improved hexagonal wurtzite structure of film، and AFM and FE-SEM analyses showed regular and spherical grain was formed on the surface. The particle size was increased from ~10 to ~30 nm after leaser irradiation. Generally، it was showed that electrical، structural and morphological properties of films improve considerably by laser irradiation.